Special equipment: 4 martini glasses
For the mousse: Melt the chocolate chips in a bowl set over a pan of simmering water. Use a spoon to drizzle swirls of melted chocolate onto the insides of the martini glasses. Refrigerate the glasses while you make the mousse.
In the bowl of a stand mixer fitted with the paddle attachment, add the peanut butter, powdered sugar, milk and cream cheese, and beat well until blended.
In a separate bowl, whip the heavy cream into medium peaks (if the cream is cold it will whip faster), it should hold up its shape, but the curl is soft when you pull up the whipped cream with the whisk. Fold the whipped cream into the peanut butter mixture with a rubber spatula.
For the peanuts: Line a baking sheet with parchment paper or a silicon nonstick baking mat.
Place the sugar in a small saucepan over medium heat and melt to create caramel, swirling the pan to cook evenly. When it's golden, a few minutes, add the peanuts and stir well to coat. Add the butter and stir it in, then immediately pour the nuts onto the prepared baking sheet to cool.
Meanwhile, spoon the mousse into the chilled martini glasses.
Once cool, break up the caramelized peanuts into small pieces by lightly chopping or snapping apart with your hands. Garnish each martini glass with a piece of caramelized peanuts.